JP3102562B1 - Polyester, sheet-like material comprising the same, hollow molded article and stretched film - Google Patents

Abstract

[Problem] To have excellent transparency, heat resistance and mechanical properties,
Provided is a polyester which hardly generates mold stains during molding, has a low residual odor and an unpleasant odor, and is excellent in fragrance retention, a sheet-like material or a stretched film, and a polyester for providing a container or a packaging material therefrom. SOLUTION: In a polyester resin in which an increase amount of a cyclic trimer when melted at a temperature of 290 ° C. for 60 minutes is 0.30% by weight or less, a sodium content of the polyester is 0.001 to 5 ppm. Characteristic polyester.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester suitably used as a material for a molded article such as a hollow molded container such as a beverage bottle, a film, a sheet, and the like, and a molded article comprising the same. In particular, the molded article obtained from the polyester of the present invention has excellent crystallization control properties, and the resulting molded article hardly generates residual off-flavor and off-odor, and is small in size with excellent transparency and heat-resistant dimensional stability. A hollow molded article, a sheet-like material and a stretched film excellent in transparency, slipperiness and dimensional stability after molding are provided. Further, the present invention relates to a polyester which has good releasability from a heat-treating mold when molding a small hollow molded article and has excellent long-term continuous moldability.

[0002]

2. Description of the Related Art Polyesters such as polyethylene terephthalate are excellent in both mechanical properties and chemical properties, and therefore have high industrial value, and include fibers, films, sheets, and the like.
Widely used as bottles.

[0003] As materials for containers such as seasonings, oils, beverages, cosmetics, and detergents, various resins are employed depending on the type of filling content and the purpose of use.

[0004] Among them, polyester is excellent in mechanical strength, heat resistance, transparency and gas barrier properties, and is therefore most suitable as a material for containers for filling beverages such as juices, soft drinks and carbonated drinks.

[0005] Such polyester is supplied to a molding machine such as an injection molding machine to form a preform for a hollow molded body, and the preform is inserted into a mold having a predetermined shape, stretch-blown and then molded into a body of a bottle. Heat treatment (heat set)
Then, it is general that the plug portion of the bottle is heat-treated (the plug portion is crystallized) if necessary.

However, conventional polyesters contain oligomers such as cyclic trimers and the like, and these oligomers adhere to the inner surface of the mold, the exhaust port of the mold gas, and the exhaust pipe. Dirt was easy to occur.

[0007] Such stains on the mold cause surface roughening and whitening of the obtained bottle. If the bottle becomes white, it must be discarded. For this reason, mold contamination must be removed frequently, and there has been a problem that the productivity of the bottle is reduced.

As a solution to these problems, Japanese Patent Laid-Open Publication No.
Japanese Patent No. 4441 discloses a method of treating polyester with water.

However, when this method is carried out industrially, the use of distilled water as treatment water is disadvantageous in terms of cost. It is common to use water. However, when water treatment is performed using industrial water, there is a problem that crystallization during molding is often too early, resulting in a bottle having poor transparency. Further, there is also a problem that shrinkage of the plug portion due to crystallization of the plug portion does not fall within the standard, resulting in poor capping.

According to the study of the present inventors, this is because when the content of metal-containing substances such as sodium, magnesium, calcium, and silicon dioxide contained in industrial water is larger than a certain value at the stage of water treatment, Metal-containing substances such as oxides and hydroxides of these metals float and precipitate in the treatment water, and further adhere to the walls of the treatment tanks and pipes, which adhere to and penetrate the polyester chips, and are formed during molding. It was found that the crystallization of was accelerated, resulting in a bottle with poor transparency. Further, there have been problems such as a metal-containing substance clogging the piping and making the cleaning of the processing tank and the piping difficult.
In particular, the content of sodium does not generate scale, but sodium ions penetrate into the chip surface layer, and crystallization proceeds with the sodium ions as nuclei, which is a major factor in whitening the bottle.

Even in the case of a bottle resin in which the catalyst has not been deactivated by the conventional water treatment, water having high hardness was sometimes used when the strands were formed into chips, but no significant decrease in transparency was observed. However, the decrease in transparency due to the above foreign matter was particularly remarkable in bottles in which the catalyst was deactivated by water treatment or the like. This is not clear,
It is considered that the deactivation of the catalyst causes the germanium compound contained in the resin as a catalyst to react with water to form particles insoluble in the resin, which become crystal nuclei and have a synergistic effect with the action of promoting crystallization.

In the water treatment stage, fines (resin fine powder) adhering to the polyester chips float and precipitate in the treated water and adhere to the treatment tank wall or the pipe wall, thereby clogging the pipe or treating. There have been problems such as making cleaning of tanks and pipes difficult.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art, and it is difficult to generate mold stains during molding, and the transparency of the bottle and the crystallization of the plug are excellent. The purpose is to provide a polyester that will be:

[0014]

In order to achieve the above object, the polyester of the present invention has a cyclic trimer having an increase of 0.30% by weight or less when melted at a temperature of 290 ° C. for 60 minutes, And containing 0.1 to 500 ppm of fines
That a polyester resin, it is.

[0015] Polyester having the above-mentioned characteristics is less likely to cause mold contamination during molding, and has a crystallization control for the plug.
Excellent transparency, heat resistance, mechanical properties,
A hollow molded article, a sheet-like material, a stretched film, and a packaging material having less residual off-flavor and unpleasant odor and excellent in fragrance retention.

The polyester of the present invention is mainly composed of a terephthalic acid or an ester-forming derivative or a naphthalenedicarboxylic acid or an ester-forming derivative and ethylene glycol as raw materials and a Ge compound or / and a Ti compound.
A polyester obtained by subjecting a polyester obtained using a compound as a catalyst to water treatment can be used.

In this case, the polyester has ethylene terephthalate as its main repeating unit in 9
It can be a linear polyester containing 5 mol% or more.

In this case, the polyester can be a linear polyester containing at least 90 mol% of ethylene-2,6-naphthalate as its main repeating unit.

In this case, the polyester formed into chips after polycondensation may be treated in a treatment tank with treated water satisfying the following conditions (a) and (b). (A) Temperature of 40 to 120 ° C (b) Treated water including wastewater from the treatment tank

In this case, the polyester formed into chips after the polycondensation may be treated in a treatment tank with treated water satisfying the following condition (c). (C) Treated water having a polyester fine powder content of 1000 ppm or less

In this case, the polyester formed into chips after the polycondensation may be treated with treated water having a sodium content of 0.001 to 1.0 ppm in a treatment tank.

The polyester obtained by the above-mentioned water treatment hardly causes mold stains during molding, has excellent crystallization controllability of the plug portion, and has excellent transparency and heat resistance.
A hollow molded article having excellent mechanical properties, residual off-flavors and off-flavors, and excellent in fragrance retention, and a sheet-shaped article excellent in transparency, slipperiness and dimensional stability after molding are provided.

In this case, a hollow molded article made of the polyester, a sheet-like material, and a stretched film stretched in at least one direction can be used.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester of the present invention is a crystalline polyester mainly obtained from an aromatic dicarboxylic acid component and a glycol component, and preferably contains an aromatic dicarboxylic acid unit in an amount of at least 85 mol% of the acid component. It is a polyester, more preferably a polyester containing an aromatic dicarboxylic acid unit in an amount of 90 mol% or more of the acid component.

The aromatic dicarboxylic acid component constituting the polyester of the present invention includes aromatic carboxylic acids such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, and diphenoxyethanedicarboxylic acid. And dicarboxylic acids and functional derivatives thereof.

Examples of the glycol component constituting the polyester of the present invention include aliphatic glycols such as ethylene glycol, trimethylene glycol and tetramethylene glycol, and alicyclic glycols such as cyclohexanedimethanol. Can be

The acid component used by copolymerization in the polyester includes terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, diphenyl-4,4 '.
-Aromatic dicarboxylic acids such as dicarboxylic acid, diphenoxyethane dicarboxylic acid, oxyacids such as p-oxybenzoic acid and oxycaproic acid and functional derivatives thereof, adipic acid, sebacic acid, succinic acid, glutaric acid, dimer acid And aliphatic derivatives thereof, and functional derivatives thereof, and alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid, and cyclohexanedicarboxylic acid, and functional derivatives thereof.

The glycol component used by copolymerization in the polyester includes aliphatic glycols such as ethylene glycol, trimethylene glycol, tetramethylene glycol, diethylene glycol and neopentyl glycol, bisphenol A and bisphenol A. And aromatic glycols such as alkylene oxide adducts of the above, and polyalkylene glycols such as polyethylene glycol and polybutylene glycol.

Further, polyfunctional compounds such as trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, glycerin, pentaerythritol, and trimethylolpropane are copolymerized within a range in which the polyester is substantially linear. Or a monofunctional compound such as benzoic acid or naphthoic acid.

One preferred example of the polyester of the present invention is
The main repeating unit is a polyester composed of ethylene terephthalate, more preferably a linear polyester containing 85 mol% or more of ethylene terephthalate units, and particularly preferably a linear polyester containing 95 mol% or more of ethylene terephthalate units, Polyethylene terephthalate (hereinafter abbreviated as PET).

Another preferred example of the polyester of the present invention is a polyester whose main repeating unit is composed of ethylene-2,6-naphthalate, more preferably 85% by mole or more of ethylene-2,6-naphthalate unit. A linear polyester containing ethylene-2,6-naphthalate units at 90 mol% is particularly preferable.
The linear polyester contained above, that is, polyethylene naphthalate homopolymer or polyethylene naphthalate copolymer containing ethylene terephthalate unit (hereinafter referred to as P
EN).

The intrinsic viscosity of the polyester of the present invention, particularly the polyester whose main repeating unit is composed of ethylene terephthalate, is preferably 0.50 to 1.30.
Deciliter / gram, more preferably 0.55-1.
20 deciliter / gram, more preferably 0.60
０．９0.90 deciliter / gram. If the intrinsic viscosity is less than 0.50 deciliter / gram, the obtained molded article or the like has poor mechanical properties. On the other hand, if it exceeds 1.30 deciliters / gram, the resin temperature rises during melting by a molding machine or the like, and the thermal decomposition becomes severe. Problems such as yellowing occur.

The intrinsic viscosity of the polyester of the present invention, particularly the polyester whose main repeating unit is composed of ethylene-2,6-phthalate, is preferably 0.40
1.00 deciliter / gram, more preferably 0.1 dl / gram.
The range is from 42 to 0.95 deciliter / gram, more preferably from 0.45 to 0.90 deciliter / gram. If the intrinsic viscosity is less than 0.40 deciliter / gram, the obtained molded article or the like has poor mechanical properties. 1.0
If it exceeds 0 deciliter / gram, the resin temperature rises during melting by a molding machine or the like, and thermal decomposition becomes severe,
Problems such as an increase in free low-molecular-weight compounds that affect the scent retention, and yellowing of the molded article occur.

The shape of the polyester chip may be any of a cylinder type, a square type, a flat plate shape and the like, and the size thereof is usually in the range of 1.5 to 4 mm in length, width and height. For example, in the case of a cylinder type, the length is 1.
It is practical that the diameter is about 5 to 4 mm and the diameter is about 1.5 to 4 mm. Further, the weight of the chip is practically in the range of 15 to 30 mg / piece.

The polyester of the present invention is obtained mainly from an aromatic dicarboxylic acid or an ester-forming derivative thereof and a glycol or an ester-forming derivative thereof. The polyester resin has a sodium element content of 0%. 0.001 to 5 ppm. The sodium content is preferably from 0.005 to 1 ppm, more preferably from 0.01 to 0.5 ppm, and still more preferably from 0.01 to 0.5 ppm.
0.3 ppm.

Further, the polyester of the present invention is obtained mainly by using an aromatic dicarboxylic acid or an ester-forming derivative thereof and a glycol or an ester-forming derivative thereof as raw materials and using a Ge compound and / or a Ti compound as a catalyst. And the intrinsic viscosity is preferably 0.68
dl / g to 0.90 dl / g, more preferably 0.69
dl / g to 0.88 dl / g, more preferably 0.7
0 dl / g to 0.86 dl / g and a density of 1.37.
g / cm ³ or more, preferably 1.38 g / cm ³ or more,
More preferably, it is 1.39 g / cm ³ or more.

When the content of sodium is less than 0.001 ppm, the crystallization rate becomes extremely slow, and the crystallization of the plug portion of the hollow molded container becomes insufficient. Therefore, the shrinkage amount of the plug portion is regulated. Since it does not fall within the value range, a poor capping phenomenon occurs, and a sheet-like material having poor dimensional stability after container molding is provided. Furthermore, if the content of sodium is to be reduced to less than 0.001 ppm, the sodium content of water treated with distilled water or reverse osmosis membrane, water subjected to highly ion-exchange treatment, etc. is very small. It is necessary to use water, which is not economically favorable. When the content of sodium exceeds 5 ppm, the crystallization speed is increased, and the crystallization of the plug portion of the hollow molded container becomes excessively large, so that the shrinkage amount of the plug portion does not fall within the specified value range. Poor capping of the plug portion results in leakage of the contents and whitening of the preform for hollow molding, which makes normal stretching impossible.

Since the above-mentioned sodium is mainly derived from treated water, these metals are present on the surface of a polyester chip or a surface layer having a thickness of about 0.5 mm or less from the chip surface.

The acetaldehyde content of the polyester of the present invention is preferably 8 ppm or less, more preferably 6 ppm or less, further preferably 4 ppm or less, and the formaldehyde content is preferably 6 ppm or less, more preferably 5 ppm or less, further preferably 4 ppm or less. is there.
When the acetaldehyde content is 8 ppm or more and the formaldehyde content is 6 ppm or more, the contents such as the container and the like molded from the polyester deteriorate in flavor and odor.

The amount of diethylene glycol copolymerized in the polyester of the present invention is preferably 1.0 to 5.0 mol%, more preferably 1.3 to 4.5 mol%, of the glycol component constituting the polyester. More preferably, it is 1.5 to 4.0 mol%. When the amount of diethylene glycol exceeds 5.0 mol%, the thermal stability becomes poor,
It is not preferable because the molecular weight is greatly reduced during molding and the acetaldehyde content and the formaldehyde content are increased. . The diethylene glycol content is 1.
If the amount is less than 0 mol%, the transparency of the obtained molded article will be poor.

The content of the cyclic trimer of the polyester of the present invention is preferably 0.50% by weight or less, more preferably 0.45% by weight or less, further preferably 0.40% by weight or less. When a heat-resistant hollow molded article or the like is molded from the polyester of the present invention, heat treatment is performed in a heating mold. However, when the content of the cyclic trimer is 0.50% by weight or more, the heating mold is used. The adhesion of oligomers to the surface sharply increases, and the transparency of the obtained hollow molded article or the like becomes extremely poor.

When the polyester of the present invention is melted at a temperature of 290 ° C. for 60 minutes, the amount of increase in cyclic trimer is 0.1%.
It is necessary that the content be 30% by weight or less. The amount of increase of the cyclic trimer is preferably 0.2% by weight or less, more preferably 0.1% by weight or less. When the amount of the cyclic trimer increased by melting at a temperature of 290 ° C. for 60 minutes was 0.3
If the amount exceeds 0% by weight, the amount of cyclic trimers increases when the resin for molding is melted, and the adhesion of oligomers to the surface of the heating mold sharply increases, and the transparency of the obtained hollow molded article or the like is extremely deteriorated. .

The polyester of the present invention can be produced, for example, as follows. That is, the polyester of the present invention has a sodium content of 0.001 to 1.0 p
It can be produced by contact treatment with pm treated water. The sodium content of the treated water is preferably 0.0
0.01 to 0.5 ppm, more preferably 0.00
5 to 0.5 ppm. As a method of the contact treatment, a method of immersing in water may be mentioned. The time for performing the contact treatment with water is 5 minutes to 2 days, preferably 10 minutes to 1 day,
The temperature is more preferably 30 minutes to 10 hours, and the temperature of water is 20 to 180 ° C, preferably 40 to 150 ° C, and more preferably 50 to 120 ° C.

In the case of industrially treating polyester chips with water, natural water (industrial water) or waste water is often reused because of the large amount of water used for the treatment. Normally, this natural water is collected from river water, groundwater, or the like, and refers to water that has been subjected to treatment such as sterilization and removal of foreign substances without changing the shape of water (liquid). In addition, natural water generally used for industrial purposes includes inorganic compounds such as silicates, aluminosilicates and other clay minerals derived from nature, bacteria, bacteria, etc., and originates from spoiled plants and animals. And many organic compounds having the following. When water treatment is performed using these natural waters, metal-containing substances such as sodium, magnesium, calcium, and silicon dioxide adhere to and penetrate the polyester chips to form crystal nuclei, and a hollow molded container using such polyester chips Was found to be very poor in transparency. In particular, sodium had a large effect.

Regardless of whether the water treatment method is a continuous type or a batch type, if all or most of the treated water discharged from the treatment tank is converted into industrial wastewater, a large amount of new water is required. In addition, there is a concern about the impact on the environment due to increased wastewater volume. That is, at least a part of the treated water discharged from the treatment tank is returned to the water treatment tank and reused, thereby reducing a necessary water amount, and reducing an influence on an environment due to an increase in the amount of wastewater. If the wastewater returned to the water treatment tank maintains a certain temperature, the heating amount of the treated water can be reduced.

From the economical point of view and the environmental point of view, in the case of batch type water treatment, treated water is repeatedly used, and in the case of continuous type water treatment, treated water discharged from the water treatment tank is returned to the treatment tank. In each case, fine particles derived from polyester chips and metal-containing substances such as sodium, magnesium, calcium and silicon dioxide in the treated water adhere to the treatment tanks and pipes of the water treatment apparatus, and This may cause contamination of the processing equipment.

A method for reducing the sodium content of the treated water in the treatment tank will be described below, but the present invention is not limited to this.

In order to reduce the sodium content and the like of the treated water in the treatment tank, an apparatus for removing sodium is provided at at least one or more places in the process before the industrial water is sent to the treatment tank for supply to the treatment tank. I do. Further, in the process until the treated water discharged from the treatment tank is returned to the treatment tank again, an apparatus for removing sodium may be installed at at least one or more places. Examples of the device for removing sodium include an ion exchange device.

In order to reduce the sodium content of the treated water introduced from outside the system to less than 0.001 ppm, it is necessary to distill the water, repeat filtration through a reverse osmosis membrane, and repeat the ion exchange treatment. Is high, which is not economically favorable.

The following is an example of a method for industrially performing water treatment, but the method is not limited thereto. The processing method may be either a continuous method or a batch method, but the continuous method is preferable for industrial use.

When water treatment is performed on polyester chips in a batch system, a silo-type treatment tank may be used. That is, polyester chips are received in a silo in a batch system and water treatment is performed. Alternatively, it is also possible to receive the polyester chips in a rotating cylindrical processing tank and perform water treatment while rotating the polyester chips to make the contact with water more efficient.
In this case, the polyester chips are charged and filled in the treatment tank, and the sodium content is 0.001 to 1.0 pp.
m of the treated water, and the treated water circulates continuously or intermittently as needed (collectively, sometimes referred to as continuous). New treated water having a content of 0.001 to 1.0 ppm is additionally supplied. The polyester of the present invention can be obtained by treating a polyester chip having the following characteristics while maintaining the sodium content in water at 0.001 to 1.0 ppm at the end of the water treatment. In any case, the sodium content of the treated water is preferably 0.001 to 0.5 ppm, and more preferably 0.005 to 0.5 ppm.

In the case of continuously treating polyester chips with water, the polyester chips are continuously or continuously intermittently received from above, and water is continuously supplied in cocurrent or countercurrent to perform water treatment. be able to.

In order to obtain a molded article having excellent heat-resistant dimensional stability and a sheet-like material having excellent dimensional stability after molding according to the present invention, the fine content of the water-treated polyester is set to 0.1%.
It is an essential requirement that the content be 1 to 500 ppm. When the fine content is less than 0.1 ppm, the crystallization rate becomes extremely slow, and the crystallization of the plug portion of the hollow molded container becomes insufficient, and therefore, the shrinkage amount of the plug portion falls within the specified value range. Because of the absence, poor capping may occur and a sheet-like material having poor dimensional stability after container molding may be provided. If the concentration exceeds 500 ppm, the crystallization rate is increased, and the crystallization of the plug portion of the hollow molded container becomes excessive. Therefore, the shrinkage of the plug portion does not fall within the specified value range, so that the capping of the plug portion is performed. It becomes defective, causing leakage of the contents, and whitening of the preform for hollow molding, making normal stretching impossible.

Here, fine particles, powder, and the like, which are considerably smaller than chips generated in the polyester production process including the water treatment process, are referred to as fines. The copolymerization component of the fine and the content of the copolymerization component are the same as those of the polyester chip, and the intrinsic viscosity is usually the same as the intrinsic viscosity of the chip, or 0.03 from the intrinsic viscosity of the chip.
(Dl / g) It is preferably in the range of high intrinsic viscosity.

When the fine content is 0.1 to 500 pp
m can be easily produced by controlling the amount of fine powder in the treated water. When water having a fine powder amount of 0 ppm is used as treated water, the fine content of the polyester may be less than 0.1 ppm, and when water having a fine powder amount of more than 1000 ppm is used, the fine amount in the polyester may exceed 500 ppm. . Here, the fine in the water treatment tank is called fine powder, and its content in the treated water, that is, the amount of fine powder, can be measured by the following measuring method.

The treated water discharged from the water treatment tank contains fine particles already attached to the polyester chips at the stage of receiving the polyester chips into the treatment tank, and friction between the polyester chips or the treatment tank wall during the water treatment. Includes polyester fines generated in Therefore, when the treated water discharged from the treatment tank is returned to the treatment tank again and reused, the amount of fines contained in the treated water in the treatment tank gradually increases. For this reason, fine powder contained in the treated water may adhere to the treatment tank wall or the pipe wall and clog the pipe. In addition, fine powder contained in the treated water adheres again to the polyester chips, and then fines adhere to the polyester chips by an electrostatic effect at the stage of drying and removing moisture. Removal becomes difficult.

The water-treated polyester chips are drained by a draining device such as a vibrating sieve or a Simon Carter and transferred to a drying step. Naturally, the water separated from the polyester chips by the drainer is a filter-type filter,
It is sent to a fine removal device such as a centrifuge and can be used again for water treatment.

For drying the polyester chips, a commonly used drying treatment of the polyester chips can be used. As a method for continuous drying, a hopper-type through-air dryer that supplies a polyester chip from the upper portion and allows a drying gas to flow from the lower portion is usually used. As a method of reducing the amount of drying gas and drying efficiently, a rotating disk type continuous dryer is selected, and heating steam, heating medium, etc. are supplied to the rotating disk and the outer jacket while passing a small amount of drying gas. The dried granular polyester chips can be dried indirectly.

As a dryer for drying in a batch system, a double-cone rotary dryer is used, and drying can be performed under vacuum or while passing a small amount of drying gas under vacuum. Alternatively, the drying may be performed while passing a drying gas under atmospheric pressure.

As the dry gas, atmospheric air may be used, but dry nitrogen and dehumidified air are preferred from the viewpoint of preventing molecular weight reduction due to hydrolysis or thermal oxidative decomposition of the polyester. The polyester subjected to the water treatment can be produced by a conventionally known production method. That is, P
In the case of ET, a direct esterification method in which terephthalic acid is directly reacted with ethylene glycol and, if necessary, other copolymerization components to remove water and esterify, followed by polycondensation under reduced pressure, or terephthalic acid It is produced by a transesterification method in which dimethyl is reacted with ethylene glycol and, if necessary, other copolymerization components to distill off methyl alcohol and transesterify, followed by polycondensation under reduced pressure. Solid-state polymerization may be further performed to increase the intrinsic viscosity and decrease the acetaldehyde content and the like.

The melt polycondensation reaction may be performed in a batch reactor or a continuous reactor. In any of these methods, the melt polycondensation reaction may be performed in one step or may be performed in multiple steps.
The solid-state polymerization reaction can be performed in a batch-type apparatus or a continuous-type apparatus as in the melt polycondensation reaction. The melt polycondensation and the solid phase polymerization may be performed continuously or may be performed separately.

In the case of the direct esterification method, Ge, Sb, and Ti compounds are used as a polycondensation catalyst, but the use of a Ge compound and / or a Ti compound is particularly convenient.

As the Ge compound, amorphous germanium dioxide, crystalline germanium dioxide powder or a slurry of ethylene glycol, a solution obtained by dissolving crystalline germanium dioxide in water, or a solution obtained by adding ethylene glycol to this and heat-treating the same are used. In particular, to obtain the polyester used in the present invention, a solution in which germanium dioxide is dissolved in water by heating, a colloidal solution, a solution in which ethylene glycol is added thereto and heated, or a solution of germanium dioxide in ethylene glycol is used. Is preferred. These polycondensation catalysts can be added during the esterification step. When a Ge compound is used, the amount used is 5 to 1 as the amount of Ge remaining in the polyester resin.
It is 50 ppm, preferably 10 to 100 ppm, more preferably 1 = 5 to 70 ppm.

Examples of the Ti compound include tetraalkyl titanates such as tetraethyl titanate, tetraisopropyl titanate, tetra-n-propyl titanate and tetra-n-butyl titanate, and partial hydrolysis thereof. Products, titanyl oxalate, titanyl ammonium oxalate, sodium titanyl oxalate, potassium titanyl oxalate, titanyl calcium oxalate, titanyl strontium oxalate, and the like, titanium trimellitate, titanium sulfate, titanium chloride, and the like. The Ti compound is formed polymer
It is added so that the remaining amount of Ti therein is in the range of 0.1 to 10 ppm.

As the stabilizer, it is preferable to use phosphoric acid, polyphosphoric acid, phosphate esters such as trimethyl phosphate, and the like. These stabilizers can be added during the esterification reaction step from a slurry preparation tank of terephthalic acid and ethylene glycol. The P compound is added so that the residual amount of P in the resulting polymer is in the range of 5 to 100 ppm.

Also, DEG copolymerized in polyester
Basic compounds in the esterification step to control the content,
For example, tertiary amines such as triethylamine and tri-n-butylamine, and quaternary ammonium salts such as tetraethylammonium hydroxide can be added.

The polyester used for water treatment has an acetaldehyde content of 10 ppm or less, a formaldehyde content of 8 ppm or less, a diethylene glycol content of 1.0 to 5.0 mol% of the glycol component, and a cyclic trimer content of 0.50% by weight. % Is preferable.

The density of the polyester chips used for the water treatment ranges from about 1.335 (g / cm ³ ) to about 1.35 (g / cm ³ ).
It is preferably in the range of 415 (g / cm ³ ).

It is also possible to simultaneously use a saturated fatty acid monoamide, an unsaturated fatty acid monoamide, a saturated fatty acid bisamide, an unsaturated fatty acid bisamide, and the like with the polyester of the present invention.

Examples of the saturated fatty acid monoamide include lauric amide, palmitic amide, stearic amide, behenic amide and the like. Examples of unsaturated fatty acid monoamides include oleic acid amide, erucic acid amido ricinoleic acid amide, and the like. Examples of the saturated fatty acid bisamide include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid Amides and the like. Examples of the unsaturated fatty acid bisamide include ethylene bisoleic acid amide and hexamethylene bisoleic acid amide. Preferred amide compounds are saturated fatty acid bisamide, unsaturated fatty acid bisamide and the like. The compounding amount of such an amide compound is 1
The range is from 0 ppb to 1 × 10 ⁵ ppm.

Metal salt compounds of aliphatic monocarboxylic acids having 8 to 33 carbon atoms, such as naphthenic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid,
Stearic acid, behenic acid, montanic acid, melicic acid,
Lithium, sodium, potassium, magnesium, calcium, and cobalt salts of saturated and unsaturated fatty acids such as oleic acid and linoleic acid can be used in combination. The compounding amount of these compounds is 10p
The range is from pb to 300 ppm.

The polyester of the present invention can be used in a hollow molded container,
It can be preferably used as a packaging material such as a tray, a biaxially stretched film, a film for coating a metal can, and the like. Further, the polyester of the present invention can also be used as one constituent layer of a multilayer molded product, a multilayer film and the like.

The polyester of the present invention may contain various additives such as known UV absorbers, lubricants, mold release agents, nucleating agents, stabilizers, antistatic agents and pigments, if necessary.
The main method of measuring characteristic values in the present invention will be described below.

[0074]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. In addition, the measuring method of the main characteristic value in this specification is demonstrated below.

(1) Intrinsic viscosity (IV) of polyester: It was determined from the solution viscosity at 30 ° C. in a 1,1,2,2-tetrachloroethane / phenol (2: 3 weight ratio) mixed solvent.

(2) Polyethylene diethylene glyco
Degraded by methanol, the amount of DEG was quantified by gas chromatography, and expressed as a ratio (mol%) to the total glycol components.

(3) Density: 25 using a density gradient tube of a mixed solvent of carbon tetrachloride / n-heptane.
Measured in ° C.

(4) Content of cyclic trimer of polyester (hereinafter referred to as “CT content”) A 300 mg sample was dissolved in 3 ml of a hexafluoroisopropanol / chloroform mixed solution (volume ratio = 2/3), and chloroform was further dissolved. Add 30 ml to dilute.
To this, 15 ml of methanol was added to precipitate a polymer, followed by filtration. The filtrate was evaporated to dryness, the volume was adjusted to 10 ml with dimethylformamide, and the cyclic trimer was quantified by high performance liquid chromatography.

(5) Acetaldehyde content of polyester (hereinafter referred to as “AA content”) Sample / distilled water = 1 gram / 2 cc placed in a glass ampoule substituted with nitrogen, sealed and extracted at 160 ° C. for 2 hours After cooling, acetaldehyde in the extract was measured by high-sensitivity gas chromatography, and the concentration was expressed in ppm.

(6) Sodium Content, Calcium Content, and Magnesium Content of Polyester About 5 to 10 g of a sample was put in a platinum crucible and incinerated at about 550 ° C., dissolved in 6N hydrochloric acid, evaporated to dryness, and the residue was reduced to 1N.
Dissolve in hydrochloric acid. This solution was measured by atomic absorption spectrometry.

(7) Silicon Content of Polyester About 5 to 10 g of a sample was put in a platinum crucible and incinerated at about 550 ° C., and then sodium carbonate was added to dissolve it by heating.
Dissolve in hydrochloric acid. This solution was measured with an inductively coupled plasma emission spectrometer manufactured by Shimadzu Corporation.

(8) Fine Content Measurement About 0.5 kg of the resin was placed on a sieve (diameter 30 cm) with a wire mesh having a nominal size of 1.7 mm according to JIS-Z8801, and 0.1% of a cationic A surfactant (alkyltrimethylammonium chloride) aqueous solution was sieved for 1 minute at a total amplitude of about 7 cm and 60 reciprocations / 1 minute while showering water at a flow rate of 2 L / min. This operation was repeated, and the resin was sieved in a total of 10 to 30 kg. The fines removed by filtration were collected by filtration with a 1G1 glass filter manufactured by Iwaki Glass Co., Ltd. together with a surfactant aqueous solution, and washed with ion-exchanged water. This is put together with the glass filter in a dryer for 10 minutes.
After drying at 0 ° C. for 2 hours, the mixture was cooled and weighed. The same operation of washing and drying with ion-exchanged water was repeated again to confirm that the weight became constant, and the weight of the glass filter was subtracted from this weight to obtain a fine weight. Fine content is the fine amount / the total resin weight sieved.

(9) Evaluation of mold stain The polyester was dried with a drier using nitrogen, and a preform was molded at a resin temperature of 290 ° C. using an M-100 injection molding machine manufactured by Meiki Seisakusho. After the plug portion of this preform was heated and crystallized by a home-made plug portion crystallizing apparatus, biaxial stretching blow molding was performed using an LB-01 stretch blow molding machine manufactured by Co-Poplast Co., Ltd., followed by about 155 ° C. Was heat-set in a mold set for 10 seconds to obtain a 500 cc hollow molded container. Under the same conditions, continuous stretch blow molding was performed, and the stain on the mold was evaluated by the number of moldings until the transparency of the container was impaired by visual inspection. In addition, as a sample for haze measurement, 5
The body of the container after 000 continuous moldings was provided.

(10) Haze (% haze) A sample was cut from the body (thickness: about 4 mm) of the hollow molded container of (9) and measured with a haze meter manufactured by Toyo Seisakusho.

(11) Density increase due to heating of the bottle cap The bottle cap was heat-treated for 60 seconds using a homemade infrared heater, and a sample was taken from the top to measure the density.

(12) The amount of fine powder (pp
m) 1000 cc of treated water passed through a JIS standard 20 mesh filter was collected from the treated water outlet of the treatment tank.
After filtration with a 1G1 glass filter manufactured by Iwaki Glass Co., Ltd., 100
After drying at room temperature for 2 hours and cooling at room temperature, the weight is measured and calculated.

(13) Sodium Content, Calcium Content, Magnesium Content and Silicon Content in Treated Water Treated water was collected from the treated water outlet of the treatment tank, filtered through a 1G1 glass filter manufactured by Iwaki Glass Co., Ltd., and the filtrate was collected by Shimadzu Corporation. It was measured with an inductively coupled plasma emission spectrometer manufactured by Toshiba Corporation.

(Example 1) An ion exchange device (9) was installed, an inlet (8) for ion-exchanged water via this device (9), a raw material chip supply port (1) at the top of the processing tank, and a processing tank. The discharge outlet located at the upper limit level of the treated water (2), the outlet for the mixture of polyester chips and treated water at the lower part of the treatment tank (3), the treated water discharged from the overflow outlet, and the outlet at the lower part of the treatment tank A pipe (6) for sending treated water from a polyester chip draining device (4) discharged from the tank to a water treatment tank again through a filtering device (5), which is a 30-μm belt-type filter made of paper. FIG. 1 shows a tower type having a capacity of 320 liters, which is provided with an inlet (7) for these finely-removed treated water and an adsorption tower (10) for adsorbing acetaldehyde and the like in the finely-removed treated water. Using to process tank polyethylene terephthalate (hereinafter, PET abbreviated) and the chip water treatment.

The limiting viscosity is 0.75 deciliter / gram, the density is 1.399 g / cm ³ , the cyclic trimer content is 0.32% by weight, the Ge residual amount measured by atomic absorption spectrometry is 49 ppm, and the P residual amount is Is 37 ppm PE
T chips are continuously charged from the upper part (1) of the processing tank at a rate of 50 kg / hour into a water processing tank containing treated water whose temperature is controlled to 95 ° C. by adjusting the sodium content to about 0.05 ppm by an ion exchange device. Started. Five hours after the start of the charging, the PET chips are withdrawn from the lower outlet (3) of the water treatment tank together with the treated water at a rate of 50 kg / hour while the PET chips are continuously charged into the water treatment tank. The treated water passed through the draining device (4) was returned to the water treatment tank again through the filtering device (5), and was repeatedly used, and then continuously operated.

The sodium content of the treated water discharged together with the chips from the outlet after the continuous operation for 72 hours is about 0.07.
ppm, the fine powder content was about 100 ppm, and the sodium content of the PET chips obtained at the same time was 0.1 ppm, and the fine content was 27 ppm. The acetaldehyde content was 2.5 ppm, and the ΔCT was 0.08% by weight. Using the PET, the density of the top surface of the plug of the hollow container obtained in the above (8) after heating with an infrared heater was 1.380 g / cm ³ and there was no problem with the haze of the trunk.
Excellent transparency of 1%, and the number of moldings to mold contamination is 1
There was no problem with 6000 times.

(Comparative Example 1) The sodium content was about 6.5 without using the ion exchange device (9) used in Example 1.
The PET chip of Example 1 was treated with water in the same manner as in Example 1 except that the treated water of ppm was supplied to the water treatment tank. The sodium content of the obtained PET chip is 9.8 ppm,
The fine content was 25 ppm. The acetaldehyde content was 2.7 ppm, and the ΔCT was 0.1% by weight. The haze of the body of the hollow container obtained in (8) above using this PET was as high as 10.1%.

[0092]

The polyester of the present invention is obtained by using as a raw material an aromatic dicarboxylic acid or an ester-forming derivative thereof and a glycol or an ester-forming derivative thereof, which have been subjected to water treatment in a chip form after polycondensation. It is a polyester having a sodium content of 0.001 to 5 ppm derived from the treatment. By using the polyester of the present invention, it is difficult for mold stains to occur at the time of molding, and the crystallization control property of the plug portion. Excellent and excellent transparency,
Provided are a hollow molded article, a sheet-like material, a stretched film, and a packaging material which are excellent in heat retention, mechanical properties, residual off-flavors and off-flavors and excellent in fragrance retention.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of an apparatus for performing water treatment of a polyester of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 raw material chip supply port 2 overflow discharge port 3 discharge port for polyester chips and treated water 4 drainer 5 fine removal device 6 piping 7 treated water inlet 8 ion-exchanged water inlet 9 ion exchanger 10 adsorption tower

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI B29K 67:00 B29L 22:00 C08L 67:02 (56) References JP-A-3-174441 (JP, A) JP-A-11-293001 ( JP, A) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B29B 13/02 C08G 63/88-63/90

Claims (9)

(57) [Claims] The amount of the cyclic trimer when melted at a temperature of 290 ° C. for 60 minutes is not more than 0.30% by weight, and
A polyester resin containing 0.1 to 500 ppm of fines , wherein the sodium content of the polyester is 0.1 to 500 ppm .
Polyester characterized by being 001 to 5 ppm. 2. Mainly using terephthalic acid or an ester-forming derivative or naphthalenedicarboxylic acid or an ester-forming derivative and ethylene glycol as raw materials
The polyester according to claim 1, wherein the polyester obtained by using a Ge compound and / or a Ti compound as a catalyst is subjected to a water treatment. 3. The polyester according to claim 1, wherein the polyester is a linear polyester containing 95 mol% or more of ethylene terephthalate as a main repeating unit.
Polyester according to any one of the above. 4. A polyester comprising 90 mol% of ethylene-2,6-naphthalate as its main repeating unit.
3. The polyester according to claim 1, which is a linear polyester containing the above. 5. The polyester formed in a chip form after polycondensation is treated in a treatment tank with treated water satisfying the following conditions (a) and (b): Item 7. The polyester according to any one of Items 1 to 3. (A) Temperature of 40 to 120 ° C (b) Treated water including wastewater from the treatment tank 6. The polyester formed into chips after polycondensation is treated with treated water satisfying the following condition (c) in a treatment tank. Polyester according to any one of the above. (C) Treated water having a polyester fine powder content of 1000 ppm or less 7. The polyester formed into chips after the polycondensation is treated with treated water having a sodium content of 0.001 to 1.0 ppm in a treatment tank. Item 7. The polyester according to any one of Items 1 to 6. 8. A hollow molded article comprising the polyester according to any one of claims 1 to 7. 9. A sheet-like material obtained by extruding the polyester according to claim 1.